Blended heterocycles

Abstract

Linear or multidimensional, crosslinking, solvent resistant oxazole, thiazole, or imidazole (i.e., heterocycle) oligomers and blends of the crosslinking oligomers and noncrosslinking comparable polymers are described. The oligomers are prepared by reacting tetraamines, diaminodiols, or diaminothiols (i.e. four-functional compounds) with poly-carboxylic acid halides, and crosslinking phenylimide end cap monomers in a suitable solvent under an inert atmosphere.

We claim: 
     
       1. A blend comprising a crosslinking oligomer and a comparable noncrosslinking polymer, the crosslinking oligomer formed by reacting: (a) 2 moles of a crosslinking phenylimide acid halide of the general formula: ##STR29##   wherein D=is an unsaturated hydrocarbon radical;   i=1 or 2; and   φ=phenyl   (b) n moles of a diacid halide; and   (c) (n+1) moles of at least one four-functional compound of the general formula: ##STR30##   wherein R is a hydrocarbon radical, Y is selected from the group consisting of --OH, --SH and --NH 2 , each Y group is attached to a carbon atom adjacent to a carbon atom to which the --NH 2  group is attached, and n is selected so that the oligomer has an average formula weight of between about 500 to about 40,000.   
     
     
       2. The blend of claim 1 wherein: ##STR31## is a radical selected from the group consisting of: ##STR32## wherein R 1  =lower alkyl, lower alkoxy, aryl, aryloxy, substituted alkyl, substituted aryl, halogen, or mixtures thereof; j=0,1, or 2;   G=--CH 2  --, --O--, --S--, or --SO 2  --;   T=methallyl or allyl; and   Me=methyl.   
     
     
       3. The blend of claim 1 wherein the backbones of both the oligomer and the polymer include benzoxazole linkages. 
     
     
       4. The blend of claim 1 wherein the backbones of both the oligomer and the polymer include benzimidazole linkages. 
     
     
       5. The blend of claim 1 wherein the backbones of both the oligomer and the polymer include benzothiazole linkages. 
     
     
       6. The blend of claim 1 comprising substantially equimolar amounts of the oligomer and polymer. 
     
     
       7. The blend of claim 1 wherein the oligomer and polymer have substantially identical backbones. 
     
     
       8. A prepreg comprising the blend of claim 1 and a reinforcing additive in fiber or particulate form. 
     
     
       9. A composite comprising the cured prepreg of claim 8.